The present invention is directed to methods of growing silicon nanowires and boron nitride nanotubes on carbon fibers by chemical vapor deposition or by a vapor-liquid-solid (VLS) method.
A low pressure environment ranging from a few Torrs to few a hundred Torrs is conventionally utilized for growth of silicon nanowires by VLS. However, the use of low pressure requires an employment of a vacuum pump and careful maintenance of the balance between reacting gases flowing in and product gases withdrawing from the reacting chamber. Additionally, the use of low pressure limits the amount of silicon source gases present in the reaction chamber for reaction as well as limits the flow rate of feeding the gases for replenishment, restricting growth in large scale.
Additionally, previous attempts at synthesis of boron nitride nanotubes have focused on using boron powder as the source of boron and ammonia as the source of nitrogen at temperatures ranging from 1100° C. to 1500° C. However, utilization of ammonia as a nitrogen source introduces challenges and difficulties into the synthesis process given the hazardous nature of ammonia.
Accordingly, there is still a need in the art for methods of forming silicon nanowires and/or boron nitride nanotubes on carbon substrates comprising carbon fibers using less hazardous materials and at atmospheric pressure.